<?php
/** 
 * @version V4.93 10 Oct 2006 (c) 2000-2010 John Lim (jlim#natsoft.com). All rights reserved.
 * Released under both BSD license and Lesser GPL library license. 
 * Whenever there is any discrepancy between the two licenses, 
 * the BSD license will take precedence. 
 *
 * Set tabs to 4 for best viewing.
 * 
*/

/*
 * Concept from daniel.lucazeau@ajornet.com. 
 *
 * @param db        Adodb database connection
 * @param tables    List of tables to join
 * @rowfields        List of fields to display on each row
 * @colfield        Pivot field to slice and display in columns, if we want to calculate
 *                        ranges, we pass in an array (see example2)
 * @where            Where clause. Optional.
 * @aggfield        This is the field to sum. Optional. 
 *                        Since 2.3.1, if you can use your own aggregate function 
 *                        instead of SUM, eg. $aggfield = 'fieldname'; $aggfn = 'AVG';
 * @sumlabel        Prefix to display in sum columns. Optional.
 * @aggfn            Aggregate function to use (could be AVG, SUM, COUNT)
 * @showcount        Show count of records
 *
 * @returns            Sql generated
 */
 
 function PivotTableSQL(&$db,$tables,$rowfields,$colfield, $where=false,
     $aggfield = false,$sumlabel='Sum ',$aggfn ='SUM', $showcount = true)
 {
    if ($aggfield) $hidecnt = true;
    else $hidecnt = false;
    
    $iif = strpos($db->databaseType,'access') !== false; 
        // note - vfp 6 still doesn' work even with IIF enabled || $db->databaseType == 'vfp';
    
    //$hidecnt = false;
    
     if ($where) $where = "\nWHERE $where";
    if (!is_array($colfield)) $colarr = $db->GetCol("select distinct $colfield from $tables $where order by 1");
    if (!$aggfield) $hidecnt = false;
    
    $sel = "$rowfields, ";
    if (is_array($colfield)) {
        foreach ($colfield as $k => $v) {
            $k = trim($k);
            if (!$hidecnt) {
                $sel .= $iif ? 
                    "\n\t$aggfn(IIF($v,1,0)) AS \"$k\", "
                    :
                    "\n\t$aggfn(CASE WHEN $v THEN 1 ELSE 0 END) AS \"$k\", ";
            }
            if ($aggfield) {
                $sel .= $iif ?
                    "\n\t$aggfn(IIF($v,$aggfield,0)) AS \"$sumlabel$k\", "
                    :
                    "\n\t$aggfn(CASE WHEN $v THEN $aggfield ELSE 0 END) AS \"$sumlabel$k\", ";
            }
        } 
    } else {
        foreach ($colarr as $v) {
            if (!is_numeric($v)) $vq = $db->qstr($v);
            else $vq = $v;
            $v = trim($v);
            if (strlen($v) == 0    ) $v = 'null';
            if (!$hidecnt) {
                $sel .= $iif ?
                    "\n\t$aggfn(IIF($colfield=$vq,1,0)) AS \"$v\", "
                    :
                    "\n\t$aggfn(CASE WHEN $colfield=$vq THEN 1 ELSE 0 END) AS \"$v\", ";
            }
            if ($aggfield) {
                if ($hidecnt) $label = $v;
                else $label = "{$v}_$aggfield";
                $sel .= $iif ?
                    "\n\t$aggfn(IIF($colfield=$vq,$aggfield,0)) AS \"$label\", "
                    :
                    "\n\t$aggfn(CASE WHEN $colfield=$vq THEN $aggfield ELSE 0 END) AS \"$label\", ";
            }
        }
    }
    if ($aggfield && $aggfield != '1'){
        $agg = "$aggfn($aggfield)";
        $sel .= "\n\t$agg as \"$sumlabel$aggfield\", ";        
    }
    
    if ($showcount)
        $sel .= "\n\tSUM(1) as Total";
    else
        $sel = substr($sel,0,strlen($sel)-2);
    
    
    // Strip aliases
    $rowfields = preg_replace('/ AS (\w+)/i', '', $rowfields);
    
    $sql = "SELECT $sel \nFROM $tables $where \nGROUP BY $rowfields";
    
    return $sql;
 }

/* EXAMPLES USING MS NORTHWIND DATABASE */
if (0) {

# example1
#
# Query the main "product" table
# Set the rows to CompanyName and QuantityPerUnit
# and the columns to the Categories
# and define the joins to link to lookup tables 
# "categories" and "suppliers"
#

 $sql = PivotTableSQL(
     $gDB,                                              # adodb connection
     'products p ,categories c ,suppliers s',          # tables
    'CompanyName,QuantityPerUnit',                    # row fields
    'CategoryName',                                    # column fields 
    'p.CategoryID = c.CategoryID and s.SupplierID= p.SupplierID' # joins/where
);
 print "<pre>$sql";
 $rs = $gDB->Execute($sql);
 rs2html($rs);
 
/*
Generated SQL:

SELECT CompanyName,QuantityPerUnit, 
    SUM(CASE WHEN CategoryName='Beverages' THEN 1 ELSE 0 END) AS "Beverages", 
    SUM(CASE WHEN CategoryName='Condiments' THEN 1 ELSE 0 END) AS "Condiments", 
    SUM(CASE WHEN CategoryName='Confections' THEN 1 ELSE 0 END) AS "Confections", 
    SUM(CASE WHEN CategoryName='Dairy Products' THEN 1 ELSE 0 END) AS "Dairy Products", 
    SUM(CASE WHEN CategoryName='Grains/Cereals' THEN 1 ELSE 0 END) AS "Grains/Cereals", 
    SUM(CASE WHEN CategoryName='Meat/Poultry' THEN 1 ELSE 0 END) AS "Meat/Poultry", 
    SUM(CASE WHEN CategoryName='Produce' THEN 1 ELSE 0 END) AS "Produce", 
    SUM(CASE WHEN CategoryName='Seafood' THEN 1 ELSE 0 END) AS "Seafood", 
    SUM(1) as Total 
FROM products p ,categories c ,suppliers s  WHERE p.CategoryID = c.CategoryID and s.SupplierID= p.SupplierID 
GROUP BY CompanyName,QuantityPerUnit
*/
//=====================================================================

# example2
#
# Query the main "product" table
# Set the rows to CompanyName and QuantityPerUnit
# and the columns to the UnitsInStock for diiferent ranges
# and define the joins to link to lookup tables 
# "categories" and "suppliers"
#
 $sql = PivotTableSQL(
     $gDB,                                        # adodb connection
     'products p ,categories c ,suppliers s',    # tables
    'CompanyName,QuantityPerUnit',                # row fields
                                                # column ranges
array(                                        
' 0 ' => 'UnitsInStock <= 0',
"1 to 5" => '0 < UnitsInStock and UnitsInStock <= 5',
"6 to 10" => '5 < UnitsInStock and UnitsInStock <= 10',
"11 to 15"  => '10 < UnitsInStock and UnitsInStock <= 15',
"16+" =>'15 < UnitsInStock'
),
    ' p.CategoryID = c.CategoryID and s.SupplierID= p.SupplierID', # joins/where
    'UnitsInStock',                             # sum this field
    'Sum'                                        # sum label prefix
);
 print "<pre>$sql";
 $rs = $gDB->Execute($sql);
 rs2html($rs);
 /*
 Generated SQL:
 
SELECT CompanyName,QuantityPerUnit, 
    SUM(CASE WHEN UnitsInStock <= 0 THEN UnitsInStock ELSE 0 END) AS "Sum  0 ", 
    SUM(CASE WHEN 0 < UnitsInStock and UnitsInStock <= 5 THEN UnitsInStock ELSE 0 END) AS "Sum 1 to 5", 
    SUM(CASE WHEN 5 < UnitsInStock and UnitsInStock <= 10 THEN UnitsInStock ELSE 0 END) AS "Sum 6 to 10", 
    SUM(CASE WHEN 10 < UnitsInStock and UnitsInStock <= 15 THEN UnitsInStock ELSE 0 END) AS "Sum 11 to 15", 
    SUM(CASE WHEN 15 < UnitsInStock THEN UnitsInStock ELSE 0 END) AS "Sum 16+",
    SUM(UnitsInStock) AS "Sum UnitsInStock", 
    SUM(1) as Total 
FROM products p ,categories c ,suppliers s  WHERE  p.CategoryID = c.CategoryID and s.SupplierID= p.SupplierID 
GROUP BY CompanyName,QuantityPerUnit
 */
}
?>